Switch mechanism for electric motors



June 24, 1924. 1,493,71

B. $.AIKMAN SWI TCH MECHANISM FOR ELECTRIC MOTORS Original File May 21.1,917 5 sheets- Sheet 1 June 24, 1924.

B. S. AIKMAN SWITCH MECHANISM FOR ELECTRIC MOTORS 5 Sheets-Sheet 3Original Filed May 2 917 ma d 498,734 s. AlKMAN 4 SWITCH MECHANISM FORELECTRIC MOTORS Original Filed y 1917 5 Sheets-Sheet 3 inflame Eurim S.

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June 24 19240 SWITCH MECHANISM FOR ELECTRIC MOTORS 5 Sheets-Sheet 5Originai Fil M y 21. 1917 16 v; 1 I I l5 Q? x V j I m Hf w 7 W N w 99 zaflying/rim Biz/22372 Patented June 24, 1924.

UNITED STATES PATENT. OFFICE.

BIiItToN s. AIRMAN, or IL AUKEE, WISCONSIN, ASSIGNOR o NATIONAL BRAKE aELECTRIC CCMP NY, or MILWAUKEE, wIsCoNsIN, A CORPORATION or wIs- CONSIN.

SWITCH MECHANISM FOR ELECTRIC MOTORS.

Original application filed May 21, 1917, Serial No. 169,997. Divided andthis application filed November 5, 1919. Serial No. 335,815. 9

I '0 all whom it may concern:

Be it. known that I, 'BURTON S. AIRMAN, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofViisconsin, have invented a certain new and useful Improvement in SwitchMechanism for Electric Motors (Case of which the following is a full,clear. concise, and exact description, reference being had to theaccompanying drawings, forming a part of this specification.

This invention relates to switch mechanism for electric motors.

In my copending application Serial No. 169.997 filed May 21, 1917, Ihave described a starting and control system for-motor drivencompressors which automatically effects the starting and stopping of themotor and' the loading and unloading of the compressor and which isparticularly characterized by provision for safe-guarding the electricalapparatus as well as the compressor itself against, damage which mightoccur as a result of continued operation under improper workingconditions.

The present application is a division of the application above referredto and has to do with the motor switch mechanism forming a part of thecontrol system above outlined. Although the embodiment of the inventiondisclosed in this application is primarily designed for use in a systemof this character, it will be understood that fea- "tures of theinvention hereinafter claimed are capable of a wider and more generaluse.

'One object of the present invention is to provide a switch mechanismespecially adapted for use with a control system of the characterreferred to.

Another object is to provide an improved means for controllingthe'starting resistance for a motor.

Another object is to rovide an improved blow-out for the switc Anotherobject is generally to improve the construction and operation ofswitches of this character.

The accompanying drawings which form a part of the present specificationillustrate one embodiment of the present invent-ion.

lows:

Figure 1 is a front elevation of a switch board attached to a compressorand support-- The figures of the drawings are as fol- Figure 2 is a rearelevation of the switch board.

Figure 3 is a side elevation, partly in section, of the switch board.This view is taken from the left in Figure 1.

Figure 4: is a side elevation taken in the. direction opposite to thatof Figure 3.

Figure 5 is a bottom plan view.

Figure 6 is a. diagram of the circuit connections for the motor.

The embodiment of the invention hereinafter described is designedprimarily for use with a polyphase induction motor of .the wound rotortype. As diagramatically illustrated in Figure 6 the Circuit from themain lines 10, 11 and 12 through the primary leads 13 of the motor iscompleted through the main switch 14 whose terminals are connected withthe main lines and the primary leads through the leads 15, 16, 17 and18. The motor secondary circuit includes the secondary leads 19, thestarting resistances 20, 21 and 22 and a cut-out switch 23 connected inparallel with the resistances for short circuiting the resistances whenthe motor has come up to its rated s eed.

Switches let and 23, as well 'as their operating mechanisms, arepreferably removably mounted upon a switch board 9 of any approved type(see Figures 1 to 4). The main switch 14 includes two relatively fixedcontactsM and 25 and two relatively movable contacts 26 and 27 carriedby a cross-head 28 actuated by a plunger 29. The relatively fixedcontacts 24 and 25 are electrically connected with suitable terminals30, and 31 mounted noon the rear of the switch board and suitablyinsulated therefrom. These terminals are connected with the feed wires15 and 16 joined by separable connectors 32 of any preferred type to theline wires 10 and 11. The relativelyfixed contacts 24,

and 25 comprises. pivot arm 33 swinging about a shaft 34- and presseddown by a spring 35. Upon vthe outer end of the arm is mounted an arcreceivingcontact 36 for making the initial and final contact with thecorresponding member of the relatively movable terminals. The conductingor actual switching contact 37 is mounted in or 31, respectively.

Th one main line wire 12 is connected directly'to the motor through thelead 39 it being unnecessary to lead this line wire through the switch-The other two primary leads 40 and 41 are connected throughsuitable-connectors 32 to the wires 17 and,

18, respectively, which are joined to suitable terminals 43 and 42 upona pair of lugs 44 and 45 forming a part of theswitch operate ingcylinder 46, the terminals being suitably insulatingbarriers 53, 54, 55and 56 which insulated from the frame of the machine.

The switch operating cylinder 46 is provided with a spriiig containinghousing 47 and a pair of stationary wiping contacts 48 and 49 which liealong-the side of this housing with plates of insulation 50 and 51interposed. The plunger 29 hereinabove referred to is actuated by apiston 52 reciproeable in the cylinder 46. The movable contacts 26 and27 carried by the cross-head 28 are constructed in substantially thesame manner as the contacts 24 and 25 except that the same are notyieldably mounted.

The cross-head 28 carries a plurality of form a pair of arc chambers 57and 58, for the contact pairs 2426 and 25'-27 respec tively. Thesebarriers are spaced apart by suitable insulating collars through whichclamping bolts are passed. The '1novable contacts 26 and 27 areconnected by means of movable wipers 59 and 60 to the stationary wipers48 and 49. It can now be seen that when the contacts 26 and 27 arebrought against the contacts 24'and 25, the line wires 10, 11 and 12will be connected directly to the primary leads 13 of the motor. I

The mechanism for actuating the piston 52 of the main switch operatingcylinder 46 I will now be described.

The cylinder head 61 of the cylinder 46 is I provided with a'boss62'which has formed therein a-plurality of valve ports and passages,later to be described. The boss is covered by a recessed cap-member 63comprisin a cylinderhaving a cylinder lining 64 wit in which slides thecylindrical portion 65 of a valve member 66 having at its upper end anenlarged shoulder or flange 67 ber 66 is normally covered by thecylinder lining 64 when the valve member is in its lowermost position.When the valve member is raised however against the action of the spring71 (see Figure 1) the port 72 effects communication between the chamber73 within the cap member 63 and a passageway 74 leading to the mainswitch operating cylinder 46. Chamber 73 is connected by the pipe 75 toany source of fluid pressure. The spring-housing 47 of the cylinder 46contains a spring 76 interposed between the upper end of the housing anda flange 7 7 of' a hollow sleeve 78. A spring 79 of less strength thanthe spring 76 is positioned within the sleeve 78 and interposed betweenan internal flange 80 thereof and the top of the piston 52. Thesesprings act to yieldably retain the piston 52 in its lowermost positionas illustrated in Figure 3.

Passageway 7O hereinabove referred to communicates with a passageway 81formed in the switchboard 9 and leading to a pair of arc blow-outnozzles 82 and 83.- These nozzles are supported upon the switch-boardadjacent the fixed switch contacts 24 and 25 and are designed to blowfiat streams of air through the compartments 57 and 58'to extinguish thearcs which might be formed at the time the main switch is opened.

The operation ofopening and closing the main switch will nowbedescribed. lVhen it is desired to close the main switch fluid isadmitted under pressure through the pipe 75 to the chamber 73 causingthe valve member 66 to be raised to the uppermost position of Figure 1and thus close off the end of member 69. The fluid under pressure thenpasses through port 72 and enters the main cylinder 46 by way of thepassage 74. This causes the piston 52 to move upwardly against'theaction of the springs 76 and 79 until the movable contacts 26and 27 areforced against the fixed contacts 24 and 25, when the main switch isclosed. When the pressure in the chamber 73 has been destroyed the valve66 is forced to return to its lowermost position of Figure 3, thuscutting 05 communication between passageway 74 and chamber 73 andopening communication between passageway 74 and the interior of veryrapidly at first and then spring 79 acts -to move it more graduallyduring the latter ited amount of air under high pressure and the valvemember 66 is provided with a bleed opening 84 therethrough. This openingpermits 'a leakage of air from the pipe 75 and chamber 73 to theinterior of the member 69 when the valve member 66 is in its uppermostposition. The main portion of the air from the air reservoir passes fromthe pipe 75 into the chamber 73 and finally into the cylinder 46 toeffect the closing of the main switch in the manner just described. Theswitch is thus held closed until the pressure in the reservoir, andhence pipe 75, has been depleted due to the escape of the air-throughthe bleed opening 8 1. At that timethe valve member 66 returns to itslowermost position and the piston 52 returns to its lowermost positionand reopens the switch, unless some means is provided for preventingsuch return. Means for this purpose will be later described inconnection with the description of the construction and operation of thecut-out switch 23.

The cut-out switch is preferably removably mounted on the switchboardnear the main switch and includes a pair of relatively fixed contacts 85and 86 and a pair of relatively movable contacts 87 and 88 constructedin substantially the same manner as the corresponding contacts of themain switch. The fixed contacts 85 and 86 are connected with suitableelongated terminals 89 and 90, respectively, mounted upon and suitablyinsulated from the rear side of the switch board 9. One end of terminal89, is connected to a secondary lead from the motor through a feed wire91 and separable connection 32. The corresponding end of the terminal 90is similarly connected to another secondary lead through a feed wire 92.The other ends of the terminals are re: spcctively connected to theupper ends of the two compressible resistances 21 and 20 by means offlexible conductors 93and 94. The third secondary lead from the motor isconnected to a feed wire 95 which leads .up

in front of the' switch-board and is connected to a terminal 96, asshown in dotted lines in Figure 2. A metallic conductor 97 (Figures 1and 2) joins this terminal with a terminal 98 extending through theswitchboard 9 to the rear thereof which terminal is electricallyconnected to the upper end of the third compressible resistance 22through always in contact with he stationary wiper" plates 102 and 103.The stationary wiper plates 102 and 103 are electrically connected tothe terminals 104 and 105 mounted upon the secondary switch operatingcylinder 106. Suitable .insulating strips 107 and 108 sepa-' rate thestationary wiper plates 102 and 103 from the cylinder. Both tel .ninals104 and 105 are electrically connected to the feed. wire 95 through asuitable conductor 109 (see Figures 2'and 4). Thus it will be seen thatwhen the cut-out switch is closed by forcing the movable contacts 87 and88 against the stationary contacts 85 and 86, respectively, current maypass from the motor through either of the feed wires 90 or 92 across thecorresponding switch contacts and through feed wire 95 back to themotor, or vice versa, without passing through theresistance.

The movable switch contacts 87 and 88 are carried by a cross-head 110supported upon a vertically movable plunger 111 secured to aipiston 112reciprocable in the cylinder 106. A compression spring 113 acts toyieldably retain the piston 112 in the lowermost position of Figure 4:.The piston 112, is raised however by the admission of fluid underpressure to the cylinder 106 through the passage 106. This passage maybe connected with any source of fluid pressure through a pipe 114. Whenthe pressure in the cylinder has been reduced the piston, 112 isreturned to its lower, position by the action of the spring 113 and thecutout switch is reopened. Mechanism is provided r'or compressing orexpanding the resistances 20, 21 and 22 to vary their effectiveresistance as the cut-out switch mechanism moves toward and from closedposition. The mechanism will now be described.

A lever 115 is pivotally mounted intermediate its ends as at 116 to thetop of the switch-board 9. The forward end thereof projects over thecut-out switch mechanism while the other end engages an insulated abovethe resistance members 21 and 22.

()ne end of the lever bears against-an in '124 fixed to theswitch-board.

Suflicient tension is maintained through:

this system of levers-to retain the several resistances in-position by aspring means whlch will now be described. This means includes atelescopic connection between the forward end of lever 115 and aninsulating stud-or collar 125 secured to and carried by the cut-outswitch cross-head 110. The telescopic connection includes a sleeve 126and a cylindrical member 127 surrounded by a strong compression spring128. Spring 128;

bears at one end against the stud or collar 125 and at the other endagainst a flange 129 formed on the cylindrical member 127. Thecylindrical member is counterbored to receive a smallspring 130 whichplaces the system of levers just described under the desired initialtension. The tension of the spring 130 may be adjusted by a set screw131' to control the value of the starting resistance. I

During the upward travel of the crosshead 110 the tension of the spring128 is gradually materially increased causing a corresponding increaseof tension through the system of levers above described. This increasedtension effects an equal compres sion in all of the resistances 20, 21and 22 thus causing a decrease in their effective resistance to permit agreater flow of current through the motor secondary circuit as the motorspeeds up. This. decrease in resistance continues until the cut-outswitch is closed and the resistances short circuited.

Mechanism is provided for preventing the opening of the main switchuntil the cut-out switch has been opened and the full resistance throwninto the motor secondary circuit. In stopping, the speed of the motor isthus gradually reduced and the danger of severe arcing at the mainswitch contacts whenthis switch opens is avoided. This mechanismincludes a latch in the form of a bellcrank lever having a substantiallyhorizontal trip arm 131 and anupright latch arm 132. This lever ispivotally mounted upon the spring housing 47 of the main switchoperating cylinder by means of a horizontal pin 133. A spring 134bearing against the arm 131 tends to move the lever to the latchingposition shown in Figure 1. The cross-head 28 carries a downwardly andrearwardly projecting rigidarm 135 having a shoulder In 136 forengagement with the upper end 13 of the latch arm 132 of the lever. Asthe cross-head 28. reaches its extreme upper position in which the mainswitch'is closed the spring 134 throws the end 137 of the latch arm 132beneath the lug 136 to retain the switch in closed condition.

The cross-head 110 of the cut-out switch carries a projection 138 whichengages the trip arm 131 of the bellcrank lever to trip the lever at thetime the cross-head reaches its lowermost position (Figure 4). This re-I the trip arm 131 permitting the latch arm 132 to lock the -main switchclosed. Fur-. ther .upward movement of the cross-head gradually reducesthe resistances and finally short circuits the resistances by closingthe cut-out switch -as above described. In order to stop the motor it isnecessary to reduce the fluid pressure in the cylinder 106.

This is accomplished by the use of an exhaust valve 139 yieldably heldto its seat by a spring 140 to close the valve port 141. Spring 140bears against a piston 143,slidable in a cylindrical portion of achamber 144 and connected to'the ,valve 139 by a valve stem 145. A smallchamber 146 is formed beneath the piston 143 and is 0011* nected witha'suitable source of fluid pressure through a pipe 147.

When it is desired to stop the motor, fluid under pressure is admittedto the chamber 146 through pipe 147 to raise the piston 143 andconsequently lift the valve off its seat to open the valve port 141.This permits escape of the fluid from the cylinder 106 and theconsequent lowering of the piston 112 to open the cut-out switch.Continued A downward movement of the cross-head 110 reduces the pressureupon the resistances 20, 21 and 22 so that their effective resistance isincreased. Finally the projection 138'on the cross head strikes the triparm 131 of the latch mechanism, thus releasing the main, switch andpermitting the same to open.

The fluid escaping fromthe switch operating cylinder 106 through thevalve port 141 into the chamber 144 may pass out through an exhaustpipe148. When a hibrieating oil is employed as the pressure medium, as inthe application above referred to, a passageway 149'may be providedconnecting the chamber 144 with the upper end of the cylinder 106 sothat as the oil escapes under pressure from the lower end supplypassage, a fluid exhaust passage, an

of the cylinder some of it may be forced up into the upperportion of thecylinder above the piston 112 to provide the necessary lubrication forthese parts.

Means may beprovided for manually closing the main switch in addition tothe fluid operated means hereinabove described. Amechanism for thispurpose is illustrated in Figures 1 and 3 and includes a lever 150pivoted at one end to the front face of the switch-board 9 as at 151.This lever is preferably provided with an anti-friction roller 152engageable with the end 153 of the rigid arm 135, hereinabove mentioned,secured to the cross-head 28 of the main switch. lVhen it is desired toclose the main switch the handle 154 of the lever 150 is raised thusforcing the roller 152 against the rigid arm 135 and lifting thecross-head 28 to the switch closing position.

Although the invention has been described in connection with a polyphaseinduction motor it is clear that it may be employed for controllingmotors of various other types.

Various changes may be made in the embodiment of the inventionhereinabove described without departing from or sacrificing any of theadvantages of the invention as defined in the following claims.

I claim 1. In combination a main switch, means for yieldably retainingsaid switch in one position, means for moving said switch to a secondposition against the action of said yieldable means, a second switch,and a latch controlled by said'second switch for holding said mainswitch in the second position.

*2. In a switch mechanism the combination of a switch having fixed andmovable contacts, a single acting cylinder, a piston in said cylinderand connected with said movable contact, means for admitting compressed"air to said cylinder, means for depleting thepressure of the live airadmitted to said cylinder, means for moving said piston to expel the airfrom said cylinder and to open said switch, and means for utilizing theair thus expelled to blow out the are formed during theopening of saidswitch.

3. In aswitch mechanism the combination of a switch havin fixed andmovable contacts, a single acting cylinder, a piston in said cylinderconnected with said movable contact, means for admitting air underpressue to said cylinder to move the piston outwardly to close saidswitch and to trap the air in said cylinder, a blow-out nozzle connectedwith said cylinder, and means for moving said piston inwardly in saidcylinder to open said switch and to force the air from said cylinderthrough said blow-out nozzle.

cylinder, a piston in said cylinder, a fluid arc blow-out nozzleconnected with said exhaust passage and a valve for effectingcommunication either between said cylinder and said supply passage toclose said switch or between said cylinder and said exhaust passage toblow out the are when said switch opens.

5. In combination a mounting board, stationary switch contacts mountedon' said mounting board, a movable switch contact, an operating cylinderfor said movable con tact, a piston movable in the cylinder, a springfor moving the piston to open the switch, jet means for directing a flowof fluid between the stationary contact and the movable contact, a valveand passageways for connecting the cylinder with said jet means when thepiston is moved by said spring.

6. In combination a stationary switch contact, a movable switch contact,an arcing chamber surrounding said contacts, a single acting cylinderhaving an operating piston moved by airwpressure for closing saidcontacts, spring means for opening the contact and expelling the airfrom the cylinder and means for projecting a jet of air expelled fromthe cylinder through said arcing chamber when the switch is opened.

7. In combination a switch, an operating cylinder for said switch, apneumatic blowout for the switch, a valve mechanism having passagesleading to the blowout, to the cylinder and to a source of fluid underpressure, said valve being operated by admission of fluid under pressureto admit fluid under pressure to the cylinder for operating the switchand means to operate the valve to connect the cylinder with thepneumatic 5 blow-out when the switch is opened.

8. In combination a switch, an operating cylinder for closing saidswitch, a pneumatic blow-out for the switch, a valve mechanism havingpassageways leading to the cylinder, to the pneumatic blowout and to asource of fluid under pressure, said valve being operated byintroduction of fluid under pressure to admit said fluid to the pistonto close the switch, said valve having leakage means to permit the fluidunder pressure to escape and means for moving the ,valve to connect thecylinder with the pneumatic' blowout when the switch is open.

for operating the switch, valve mechanism for said cylinder, said valvemechanism comprising a pair of ports and a movable valve element adaptedto obstruct one of said ports at a time, a passage communi' eating withthe cylinder, a passage communicating with the blowout nozzle and one ofsaid ports, a passage communicating with one of said ports andadaptedfor connec- 13o tion with a' source of fluid under pressure, said valvemechanism being actuated by the fluidpressure to admit fluid underpressure to the cylinder, aspring for moving said movable va'lveelements to connect the cylin'der with the blowout nozzle and means.

for opening the switch.

10. lin combination a main switch, a blow.- out nozzle for said mainswitch, an operating cylinder for closin said main switch, means foradmitting n I to said cylinder to close the switch, a meanda chanicaldetent for holding said switch in closed osition, a'. spring for movingthe piston in said cylinder'and to open the. switch, a resistancecontrolling means for connecting the cylinder with the blowout nozzle.

11. In combination a switch, a blowout nozzle for the switch, a cylinderfor closing the switch, a mechanical detent for holding said. switch inclosed position, a spring for opening said switch, a valve and a conduitfor connectin said nozzle with thecylinder to blow out t e are when theswitch lowed to open. Y 1

12. The'co'mbination of a switch, means forclosing said'switch includinga piston and a single acting cylinder, "a pneumatic blow-out connectedwith said cylinder so that air is forced through said blow-out by thereturn movement of said piston, and;

initial movement of said piston and a slower. .final movement of saidpiston -14. The combination of a switch, a"cylin-- der, a piston in-saidcylinder for actuating,

said switch, means for admitting a limited amount of'fluid under.pressure to said cyle *inder to close said switch, and means permittinga leakage of .said' fluid to efiect a reopening of said switch. after apredetermined time interval.

15. The combination of a switch, a cylinder'," -1a piston in saidcylinder for actuating saidfsw'itch, means for admitting a limitedamount of fluid under pressure to' said cylinder to close said switch, alatch for holding said switch closed, and leakage means for depletingthe fluid pressure after apredetermined'time, interval.

16. The combination of a switch, a piston and cylinder for actuatingsaid switch, a

id under pressure switch adapted to release said detent and valve is-al-' passage for admitting fluid under pressure to said cylinder,fanexhaust passage for said cylinder, a valve actuated by the fluid underpressure for efiecting communication be tween said cylinder and saidfluid inlet passage, and movable to eiicct communication between saidcylinder and said exhaust passage, anda bleed opening through'said valvecommunicating with said fluid inlet passage and said exhaust passage.

17. The combinationof a switch having fixed and movable contacts, apiston and cylinder for actuating saidanovable' contact, means forconnecting saidfiied contact'with a source ofelectric current, aterminal sup ported by said cylinder, and an extensible conductorbetween said terminal andsaid movable contact including a stationarywiper plate connected with'said terminal and ,a movable wiper plateengaging said stationary plate and connected with said movable contact.

18. In combination a switch, said switch. comprising a relativelystationary and a relatively movable contact, an operating cylinder forsaid switch, a piston rod for said cylinder, said piston rod beingconnected to the movable contact, said cylinder having a spring housing,said piston rod passing through said housing, a spring in said housing,normally holding said contacts separated, a piston in said cylinderconnected to .said rod,.-a stationary wiper plate mounted on the sideof. said springihousing, and a movable wiper contact carried by saidpiston rod and connected. to said movable contact.

'- 19. In combination a mounting board, stationary and movable contactsmounted on said board, an operating cylindenmounted on said board, apiston rod supporting the movable contact barrier chambers surrounding'the. movable and stationary contacts,

X said barrier chambers being mounted on said piston ma'stai aary .wipercontactssupported rby"'the cylinder, and movable wiper contacts"supportedby" the piston rod.

20. The combination of a switch, a cylinder, a piston in said cylinderfor actuating said'switch, a port for admitting fluid pres sure to saidcylinder to close said switch, an exhaust port of greater capacity thansaid first'named port,-andvalve mechanism for controlling said ports toeffect a closing of said switch or a quickopening of said switch. 21.The combination of a switch, a cylinder, a switch actuating piston insaid cylinddi and means for-admitting fiuid'to or from said cylinder toactuate said piston, said means being constructed-to' permit the flow offluid-faster in one direction thanithe other so as to efiect arelatively slow closing of the switch and a rapid opening of the switch.'4

22. The combination of a switch, a cylinder, a switch actuating pistonin said cylinder, a fluid inlet port, a fluid outlet port,

switch and for opening said second named port to open said switch with aquick action.

24;. The combination'o'f a switch, means for closing. said switch andfor holding said switch closed for a predetermined period, meansoperable to hold said switch closed for an indefinite period, and meansfor effecting the opening of said switch wit-ha quick action whenreleased.

25. The'combination of a switch, fluid means for closing said switch andfor bold ing said switch closed for a predetermined period, and meansfor opening said switch with a quickaction after said switch has beenreleased.

26. The combination of a switch and fluid means for closing said switchand for hold ing said switch closed fora predetermined period, saidmeans including a valve mecha nism for effecting a quick opening of saidswitch after said switch hasbeen released. 27. In combination, a mamswitch, means for closing the main switch and holding it closed for apredetermined time only, a starting resistance cut-out switch in serieswith the main switch and means controlled by said latter switch forholding'the main switch closed until the latter switch is opened.

28. In combination, a pivoted contact member having an arcing horn and amain contact portion, a cooperating movable. switch member having a maincontact portion and'an arcing horn, means for moving said members intoengagement with each other to bring the arcing horns into engageinentfirst and thereafter to bring the main contact portions into engagement,and an arcing chute surrounding saidcontact members and movable with thesecond contact member.

29. 'In combination, a relatively stationary switch member, a relativelymovable switch member, a spring tending to separate said members, andpneumatic means operated by said spring for projecting a blast of fluidupon the'contact members as they are separated, said movable memberhaving mo tion for creating said pneumatic pressure before the contactsare separated.

30. In combination, a pair of contact members, one of said members beingmovable with respect to the other, a spring for moving said movablecontact member, and pneumatic means operated by said spring fordirecting a blast of air upon the contacts when they separate, saidmovable memher having motion prior to. separation of the'swit'chmembersfor creating said pneumatic pressure.

31. In combination, a pair of switch members, a single actin cylinderhaving a pismoving the movable member into engage-- ment with thestationary member, a spring for moving said piston and movable switchmember to open the switch, means for admitting a predetermined quantityof air under pressure to said cylinder and for thereafter exhausting thesame, said means directing the air compressed by the return movement ofthe piston upon the switch members when the switch is opened by saidspring.

33. In combination, a switch, a cylinder having a piston for operatingsaid switch, an auxiliary reservoir, means for connecting the auxiliaryreservoir to said switch cylinder, and means for bleeding away thepressure of said auxiliary reservoir and switch cylinder;

34:. In combination, a switch, a cylinder having a piston for operatingsaid switch, an auxiliarygeservoir, means for connecting the auxfliaryreservoir to said switch cylinder,-and means for bleeding away thepressure of said auxiliary reservoir and switch cylinder, a mechanicaldetent for holding the switch closed.

35. In combination, 'a switch, a cylinder having a piston for operatingsaid switch, an auxiliary reservoir, means for connecting the auxiliaryreservoir to said switch cylinder, and means for bleeding away thepressure of said auxiliary reservoir and switch cylinder, a mechanicaldetent for holding the switch closed, and a cutout switch controllingsaid mechanical detent.

ton driven outwar 'ly by fluid pressure for 36. In a switch, astationary contact mem-' one spring with the top of the other spring anda housing for enclosing said springs,

said first spring at its upper end engaging the housing, said pistonbeing adapted to engage the lower end of the lbarrel whereby the firstspring applies its pressure directly to .the piston and thereafter thesecond spring applies pressure to the piston for giving the pistonarapid start but relatively slow travel towards the end of its motion.37. In a switch, a stationary contact member, a relatively movablecontact member, a piston, a cylinder, means comprising a source of fluidpressure for moving the p1ston to close the switch, and means for movingthe piston to open the switch, said means comprising a pair ofconcentric springs, a barrel member connecting the lower end of onespring with the top of the other spring and a housing for enclosing saidsprings, said first spring at its upper end engaging the housing, saidpiston being adapted to engage the lower end of the barreliwhere by thefirst spring applies its pressure directlyto the piston and thereafterthe second spring applies pressure to the piston for giving the piston arapid start but relatively slow travel towards the end of its motion,and a blow-out nozzle connected to the cylinder for directing a blast ofair upon the switch contact. 1

38. In combination, a cylinder, a piston,

a air of switch members including a movab e member connected to saidpiston, a pair of s rings of different strength for moving t e pistoninwardly to separate the contact, the stronger spring first applying itspressure directly thereafter through the weaker spring in order to givean addimovable member to open position and pneumatic means operated bythe spring to pro-' tional impulse to the piston for giving a quickoperation of the blow-out nozzle, and a blow-out'nozzlefor directing theair compressed by the inward movement of the piston upon the switchcontact when they separate.

39; In combination, a pair of, switch members one of said members beingmovable, a

cylinder having a piston connected to said movable switch member, ahousing of reduced diameter mounted upon said cyhnder, I

a, spring in said housing for opposing the closing movement of thepiston, a stationary contact mounted along the side of the housing, anda movable wiper connected to the movable switch member. 7

40. In combination, a switch having a relatively stationary and arelatively mov able member, a spring for throwing the they areseparated. I

41. The combination of a main switch ject a'blast of air between themembers as having means for closing-the same, a spring for opening thesame,*a latch for holding the main switch in closed position, the,closing means for the main switch comprising the main switch in closedposition, the closing means for the switch comprising a piston andcylinder and an auxiliary reservoir forholding said main sw tch closedfor a predetermined time only, a latch for holding the switch closed foran indefinite time, means for tripping out the latch, and a blowoutnozzle connected with the cylinder, the

inward movement of the piston under the influence of the spring causinga flow of air through said blow-out nozzle.

43. In combination, a main switch, a blow-out nozzle for the mainswitch, an operating cylinder for closing said main switch, means for 1admitting fluid under.-

pressure to said cylinder to close the switch,

a mechanical detent. for holding the switch in closed position, a springfor moving the piston in said cylinder to open the switch, means adaptedto release saiddetent and valve means for connecting the cylinder withthe blow-out nozzle.

442 In an electric controlling device for controlling'a motor operatedpump, a motor circuit, a circuit changer for said circuit, a pressurecylinder for operatin said circuit changer, a valve controlling t eadmission of pressure to said cylinder, a connection between said valveand said cylinder, and

means in said connection for permitting a free flow of fluid out of saidcylinder.

45. In an electric. controlling device for controlling the electricmotor circuit of a motor operatedpump,'a circuit controller, a pressureactuated motor for actuating the circuit controller, a valve,eontrollingthe motor,a connection between-the valve and the-motor, andmeans in the connection retarding the flow from the valve to the motorbut permitting a free fiow from the motor.

46; In an electric controlling device, the.

combinationof'a circuit controller, a pressure actuatedmotor foractuating the cir-v cuit controller, a valve controlling the motor,

a connection between the valve and the mo tor, and means in theconnection retardingthe iiowfrom the valve to the motor and permitting afree flow from the motor.- 4L7. In combination, a switch, a cylinder forclosing the switch, a pressure controlled valve, a fluid pressureconnection between the valve and the cylinde'r,,and a quick releasevalve for said cylinder for quick open ing of the switch when thepressure in the cylinder decreases below a predetermined value.

48. In combination, a switch having a contact, a blow-out for thecontact, a'pressure operated cylinder for closing the switch contact, as ring for opening said contact, a connection ibr fluid pressure to thecylinder, and a nick release valve for the cylinder for connecting saidcylinder with said blowout.

49. In combination, a switch having a con tact, a blow-out for theswitch contact, a fluid pressure operated cylinder for closing theswitch contact, a fluid pressure connection for the cylinder for closingsaid switch contact, and a quick release valve connecting the cylinderand the blow-out.

50. In combination, a switch, a fluid pressure operated cylinder forclosing the switch, means for admitting a charge of fluid pressure tothe cylinder for holding it closed for a predetermined time, a leakageport for dissipating said charge and a quick release valve forpermitting the switch to open quickly after the fluid pressure has beendepleted to a predetermined point.

51. In combination, a switch, a fluid pressure operated cylinder forclosing the switch, means for admitting a charge of fluid pressure tothe cylinder for holding it closed for a predetermined time, a leakageport for dis-' sipatin said charge, and a quick release valve forpermittin the switch to open quickly after the fluid pressure has beendepleted to a predetermined point, and a blowout for theswitch'connected to the cylinder throu h said quick release valve.

52. In combination, a swit h having a stationary and movable contact, acylinder having a piston connected to the movable contact, a spring formoving the piston and 'movable contact, a fluid pressure connectionforthe cylinder, a leakage port tending to deplete the pressure in saidcylinder and a quick release valve for said cylinder. v 53. Incombination, a switch having a stationary and a movable contact, acylinder for operating the movable contact, means i tending to open themovable contact, a fluid pressure connection for the cylinder, and aquick release valve for exhaustin the pressure in the cylinder when saidpressure drops below a predetermined value.

54. In combination, a switch having a stationary and a movable contact,a cylinder for operating the movable contact, means tending toopen themovable contact, a fluid pressure connection for the cylinder, and aquick release valve for exhausting the pressure in the a cylinder whensaid pressure drops below a predetermined value, a blowout for theswitch contact, and a connection between said blow-out and saidquickrelease valve. i

55. In combination, a main switch, a cutout switch, a first fluidpressure operated cylinder for the mainswitch, a leakage port and aquick acting release valve for said cylfor closing said main switch, acut-out switch, in series with a main switch, means for closing thecut-out switch and means controlled by the cutout switch for holdingsaid main switch closed, and means controlled by said holding means forautomatically opening the main switch.

57. In combination, a main switch, means for closing said switch, aspring for opening said switch, a latch for holdingsaid main switchclosed, a cut-out switch in series with a main switch, a spring foropening the second switch, means for hol ing the second switch closed,said latchfor the main switch being tripped by opening of the cut-outswitch.

58. In combination, a plurality of switches, means for closing saidswitches in a predetermined order, means for each switch individuallytending to open it, means for holding said switches closed and meanscon- .trolled by opening of one switch for disabling the holding meansof an adjacent switch. e

59. In combination, a plurality of switches, means for closing saidswitches in a predetermined order, means for each switch individuallytending to open it, means for holding said switches closed, said meansbe-' ing operable only in a different predetermined order from that ofclosing the switches.

60. In combination, a first switch, a second switch, means for closingthe first switch, means for closing said second switch after the closingof the first switch, spring means for throwing the first switch openautomatically, means for throwing the second switch open automaticallyand holding means for the first switch adapted to be tripped out by theopening of the second switch.

61. In combination, a first switch, a second switch, pneumatic means forclosing the first switch, spring means tending to open the first switch,fluid pressure means for closing the second switch, spring means tendingto throw the second switch open, mechanical holding means for holdingthe first switch closed, said holding means being tripped out by openingof the second switch and a valve controlling the opening of the secondswitch.

62. In combination, a first switch, a sec ond switch, pneumatic meansfor closing the first switch, spring means tending to throw said switchopen, a quick release valve for permitting rapid opening of the firstswitch,

mechanical detent means for holding the first switch closed, a secondswitch, fluid pressure means for closing the first switch, spring meanstending to open said first switch, a'quick release valve for permittingrapid opening of said second switch and means on. thesecond switchcontrolled by opening of said second'switch for tripping .out themechanical holding means for the first switch.

63. In combination, a pair of switches,

fluid pressure means for closing the switches in predetermined order anddetent means for the switch first'closed for compelling .opening of theswitches in the reverse of said predetermined order. I

645-111 combination, a pair of switches, fluid pressure means forclosing; the said switches in a I predetermined order, detent I meansforthe switch first closed for compelling opening of the switches in thereverse order, andquick release valves for said fluid pressure means forpermitting rapid opening of each ofsaid switches.

65. In combination, aswitch, a cylinder having a piston 'for operatingsaid switch, aniaux-iliary- .reservoir,means for connecting theauxiliary reservoir to said, switch cylinder, means for bleeding awaythe' pressure of said. auxiliary reservoir and said switch cylinder-,ancl means for, recharging; I

opened.

the auxiliary reservoir when'the switch is 66.111 combination, a'switch,a cylinder having-a piston for operating said switch,

a main reservoir, an auxiliary reservoir,-

and said switch? cylinder, fa. mechanical pressure themain reservoir fortripping said mechanic alfdetent and for recharging said auxiliaryreservoir, I I I In witness whereof I hereunto subscribe n y name this30th day of October'l9l9. BURTON s. AIK AN.

